Did you manage to solve this problem? I have similar problem with 18F67J10 and ENC28J60. I think it could be the CCS TCP/IP stack but I am not sure. The DHCP work fine in most cases but in some cases, ...
Without the sleep instruction, it doestn't loop. Everything works fine. In fact sleep work fine if IDLEN = 1. I guess I will just settle with sleeping in idle mode.
I am using PIC18F67J10 to develop a project. I need to put the PIC to sleep but it seems that the MCU resets everytime I put it to sleep. The specs states